Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
418 AM EDT Thu Oct 18 2018

Valid 12Z Thu Oct 18 2018 - 12Z Sun Oct 21 2018


Day 1...

...Southern and Central Rockies...
A closed low centered over Utah opens Thursday and begins to eject
east Thursday night. Associated high elevation snow is expected
over Utah and Colorado Thursday. While widespread heavy
accumulations are not expected, locally heavy totals are possible
across some of the higher peaks with moderate probabilities for
four inches in the Uinta, Wasatch, San Juan, and Sangre de Christo
ranges. As the low continues to weaken and track further east,
precipitation is expected to diminish across the region by early
Friday. 

The probability of significant icing (0.25 inches or more) is less
than 10 percent.

Day 2...

The probability of significant snow (4 inches or more) is less
than 10 percent.

The probability of significant icing (0.25 inches or more) is less
than 10 percent.

Day 3...

A reinforcing trough swings southeast from Manitoba Saturday,
reaching the central Appalachians Saturday night. Banding is
likely on the west side of the vorticity lobe with a localized one
or two inches across the Midwest. However, the addition of Great
Lake moisture and upslope on the western side of the Allegheny
Plateau raises a risk low to moderate risk for 4 inches in the
highest portions of the Allegheny Highlands of West Virginia as
temperatures crash Saturday night.

The probability of significant icing (0.25 inches or more) is less
than 10 percent.

Jackson